Before you hop into a public game, go to the tutorial and jump in the command chair and get to know what the buttons do and where they are. That way when you join a game your not searching for one button for 2 min.

With both dont let your team defend, it can be very easy to put support buildings in a room so they can get health but if they are not pushing it will not help one bit when the other team can be making gains on the other side of the map. Some times its good to defend like if its right next to your base but you do not need the entire team helping.

Marines unless your very stratigic and want shotguns in three minutes, I go from atleast having a phasegate at 7 min with armor 1 or guns 1 done or on the way. Not many comms get gernades but I do early game because they are cheap. When you want to place another tech point always put down an observatory first and when the tech point is down always put atleast one infantry portal. Lastly your their to comm your team not babysit them, do give them med packs and ammo but remeber those really add up in rez when you need to upgrade stuff

Aliens I always go crag hive first, unless your team openly states they want something else. You may not need to communicate as much with aliens but you are the commander and you should tell your teammates where the best place to hit is. Also make drifters they make building structures go by faster and all alien comms should use them. Put structures where your aliens are going to be attacking from. Remeber to get three of a kind of sub evolutions like shells, spears. Lastly if you do go shade at some point, rember that it gives you ink that ca be used against the marine comm scanning very helpfull when he is arking.

Lastly because this is very long. Dont ever have 200 rez after that is just rez going to be wasted. Also when you comm always have your teammates hit the weakest point on the map. Dont have your team go head on that is just going to get you dead. So scan the map and see where the less amount of marines/aliens are coming from.